1. Field of the Invention
This invention generally relates to an electrical connector which is mounted on a printed circuit board, and more particularly to one provided with circuit board retention structure.
2. Description of the Prior Art
There are currently numerous electrical connectors commercially available which are mounted on a printed circuit board. In order to aid in placement accuracy, location assistance or to prevent connector movement while mounting to the printed circuit board, there is a need to add a hold down feature. Generally, it is most cost effective to add such a function to an existing component in an assembly, rather than adding a new component. For instance, if a housing has an integrated, molded orientation post, a crush rib could be added which would provide interference with the hole on the printed circuit board. However, if the same approach is used with a through hole component in a variable pin count connector and every one of the contacts contains a retention feature, as the connector length grows longer, the number of hold down increases, the insertion force would accordingly increase even be out of a desirable range. So, to meet the requirement of a maximum force, only a part of the contacts are modified to have the retention feature.
U.S. Pat. No. 6,634,893 B1, issued to Hon Hai, discloses such an electrical connector having some contact tails with retention features and others contact tails without retention feature. The contact tails are overlapped in pairs and each pair of contact tails is inserted into the through hole of a printed circuit board. Some contact tails with retention features, called retention contact tails, have longitudinally extending protrusions deviating from each other for bearing against peripheral walls of the through holes of the printed circuit board. The retention contact tail defines a notch at a side thereof and has a barb protruding outwardly from an opposite side thereof. In use, the barbs of the retention contact tails will be subject to forces substantially along a longitudinal direction of the connector.
The present invention concerns contact tails of the above kind in general but with a different design in creating the retention force.